This invention relates to apparatuses for controlling the rigidity of a vehicle body. In a vehicle having a collision impact energy-absorbing construction, an apparatus consistent with the present invention can control the rigidity of a frame or other components of a vehicle body so as to obtain an adequate reaction load in a collision, depending upon the form of the collision and/or an object against which the vehicle collides.
Applicant of the present application has previously devised, and disclosed in JP 11-291951 A, an apparatus for controlling the rigidity of a vehicle body, which uses piezo-electric actuators disposed on side frames provided at right and left sides of the vehicle to adaptively generate a force restraining the side frames from deforming or a force assisting the side frames in deforming at each point of the side frames in the event of a collision, thereby enhancing or abating the rigidity of each side frame so as to have optimum impact energy absorbency conforming with the form of the collision. To be more specific, this apparatus is configured, for example, to render the both side frames less rigid in the event of a full frontal crash where the vehicle collides with its entire front engaged, and to render one of the side frames more rigid in the event of an offset frontal crash where the vehicle collides with part of the front of the vehicle engaged such that the collision load concentrates on the one of the side frames; thus, an optimum impact energy absorption can be ensured in either form of the collision.
In addition to the adaptive rigidity control according to the form of the collision such as a full frontal or offset frontal crash as discussed above, an apparatus for controlling the rigidity of a vehicle body as above may conceivably be configured to exercise a control over a reaction force applied to an object against which the vehicle collides according to the dimensions of the object.
However, the construction and underlying mechanism of the aforementioned apparatus relies on the action of the piezo-electric actuators for generating a force resisting the collision load, i.e., a great force for receiving the collision force, and thus requires a large amount of electricity. This disadvantageously results in unfavorable upsizing of the piezo-electric actuators and of battery for powering the piezo-electric actuators.
Illustrative, non-limiting embodiments of the present invention overcome the above disadvantages and other disadvantages not described above. Also, the present invention is not required to overcome the disadvantages described above, and an illustrative, non-limiting embodiment of the present invention may not overcome any of the problems described above.